With reference to FIGS. 1 and 2, a conventional high pressure sensor is shown, generally indicated at 10. FIG. 2 is an enlarged cross-sectional view of the housing 12 of FIG. 1. Thus, the housing 12 houses a portion of a metal fuel port 14. A pressure sensing element 16 is mounted on an end of the port 14. The sensing element 16 is connected to an application-specific integrated circuit (ASIC) 18 by bonding wires 20. The ASIC 18 is connected to bond pad 31 on a printed circuit board (PCB) 22 by bonding wires 21. The ASIC 18 is mounted on the PCB 22 that is adhered to a spacer 23. Compliant pins 24 (typically three pins 24 not disposed on a single plane) are injection molded into a connector 26 to provide an input voltage, a ground, and an output voltage to the PCB 22.
FIG. 3 is a top view of the housing 12, shown with the pins 24 ready to be inserted into pin holes 28 in the PCB 22. With reference to FIG. 4, which is a side view of the pins 24 coupled with the PCB 22, since the pin holes 28 and thus the pins 24 inserted therein are on the same side of the PCB 22, the pins 24 can tilt during assembly. FIG. 5 shows the assembly forces on the PCB 22 during insertion of the pins 24. Since the modulus of the adhesive 30 is low, when one side of the adhesive 30 is under tension and the other side thereof is under compression, the PCB 22 is tilted.
In addition, with reference to FIGS. 4 and 6, vibrating force from portion of a cable (not shown) and the connector 26 that is transferred to the pins 24 can also tilt PCB 22 up and down. As shown in FIG. 7, in the conventional sensor 10, the sensing element 16 is mounted to the port 14 via a first bonding material or glass frit 32 and the ASIC 18 is mounted to the PCB 22 by a second bonding material or adhesive 34. The port 14 is provided in an opening 33 in the PCB 22. Vibration forces F from the cable coupled with the connector 26 can induce a high relative displacement between the port 14 and the PCB 22. Thus, vibration can cause the adhesive 34 and ASIC 18 to move up and down with PCB 22, while the glass frit 32 and the sensing element 16 remains more stationary. Such relative movement can cause the bonding wire 20 at either end thereof to be broken.
Thus, there is a need in a high pressure sensor to reduce assembly and vibration displacements on a PCB and thus make the bonding wire connection between an ASIC and pressure sensing element more robust.